Interferons and other cytokines in head and neck cancer

Ipomoea obscura ameliorates cyclophosphamide-induced toxicity by modulating the immune system and levels of proinflammatory cytokine and GSH

Ipomoea obscura L. is a widely used medicinal plant. The objective of this study was to investigate its protective activity against cyclophosphamide (CTX)-induced toxicity in mouse models. Swiss albino mice were treated intraperitoneally with CTX (25 mg/kg body weight) along with I. obscura extract (10 mg/kg body weight) for 10 days. Extract significantly reduced myelosuppression caused by CTX and improved the relative organ weight, total white blood cell count, and bone marrow cellularity. The elevated levels of parameters related to pathophysiology of the liver, namely glutamate pyruvate transaminase, alkaline phosphatase, and lipid peroxidation, were significantly reduced by extract treatment. Reduction of liver and intestinal glutathione levels of CTX-treated animals was reversed by I. obscura. The lowered levels of cytokines, namely IFN-γ, IL-2, and granulocyte-monocyte colony-stimulating factor after CTX treatment were found to be increased in I. obscura treated animals. Treatment with I. obscura could also decrease the level of proinflammatory cytokine TNF-α. The data suggested that I. obscura can act as a potent chemoprotective agent and can be used as an adjuvant in chemotherapeutic applications.

Recombinant vaccinia virus expressing interleukin-2 invokes anti-tumor cellular immunity in an orthotopic murine model of head and neck squamous cell carcinoma

Induction of T cell immunity following vaccination with a recombinant vaccinia virus expressing interleukin-2 (rvv-IL-2) was studied in an orthotopic murine model (SCCVII/SF) of head and neck squamous cell carcinoma (HNSCC). Mice bearing SCCVII/SF cells in the oral cavity were vaccinated subcutaneously with irradiated, rvv-IL-2-infected tumor cells combined with intratumoral injection of rvv-IL-2, resulting in recruitment of larger numbers of CD3+ CD8+ and CD3+ CD4+ T cells in the spleen (Sp) and tumor-draining lymph nodes (TDLN) compared to control vaccine rvv-lacZ. Tumor-specific CD8+ T and CD4+ helper T cell activities in the Sp and TDLN were significantly increased in rvv-IL-2-treated mice. Sp and TDLN cells from rvv-IL-2-treated mice secreted significantly higher levels of IL-2 and IFN-gamma compared to rvv-lacZ-treated mice, while the levels of IL-4 and IL-5 were comparable. Numbers of IFN-gamma-secreting cells were also higher in rvv-IL-2-treated mice. Vaccine efficiency was completely abolished by depletion of CD8+/CD4+ T cells from rvv-IL-2-vaccinated mice. We conclude that anti-tumor activities of rvv-IL-2 are due to the induction of tumor-specific CD8+ CTL and CD4+ Th1-type helper T cells, and rvv-IL-2 may be used for treatment of HNSCC patients, since SCC VII/SF closely resembles HNSCC.

Interferon-gamma (IFN-gamma) as a potential radio- and chemo-protectant

Interferons (IFN) have had increasing clinical usage in the treatment of a variety of disorders, at times being used in combination with chemo- or radiotherapy. However, interferons may have inhibitory effects on hematopoietic stem cell proliferation and the effects of this cytokine's use on long-term hematologic function have not been studied. We performed the competitive repopulation assay in the murine system, using cells exposed to irradiation or single-dose chemotherapy with or without concomitant IFN-gamma use. IFN-gamma alone had no deleterious effects on hematopoietic stem cell productivity. We measured the repopulating ability of exhaustible multilineage precursors that were present at early stages of marrow repopulation after competitive repopulation (30 days). These progenitors were minimally impacted by cyclophosphamide (CTX) with or without IFN-gamma. Irradiation (XRT) and CTX alone produced significant repopulating defects in the most primitive hematopoietic stem cell, PHSC. Addition of IFN to either treatment regimen resulted in protection of PHSC, with improved repopulating ability, although the levels of donor marrow reached control levels only when CTX and IFN were used together. The results of multiple use of IFN with chemotherapy must be studied further, but IFN may offer hematologic radio- and chemoprotection, in addition to its antitumor properties in clinical protocols for treatment of cancers.

The immunopharmacology of head and neck cancer: an update

Patients with head and neck squamous cell cancer have cell-mediated immune defects and anergy, which progress with disease. T-lymphocytopenia and dysfunction, monocyte dysfunction, prostaglandins, antigen-antibody complexes, serum and cell suppressive factors, radiation therapy and poor nutrition with zinc deficiency all contribute. Nevertheless, cell-mediated immunoreactivity to tumor is manifest in the majority of the patient's blood and regional nodes, and in the tumor itself by tumor-infiltrating lymphocytes. Lymphocytes from these sources cloned in the presence of interleukin-2 +/- tumor extracts show relatively specific cytotoxicity against squamous cell cancer. Humoral immunity is intact, and increased IgA and IgE levels and antibodies reactive to tumor antigens are common. Tumor-associated antigens detected in serum and tumor include carcinoembryonic antigen, tumor polypeptide antigen, squamous cell cancer antigens, tumor antigen-4 and various mucin antigens. The mucin antigens, in particular, can elicit T-cell responses. Humoral reactivity to such antigens is manifest in circulating immune complexes and immunoglobulin coating of tumor surfaces. Immunotherapeutic efforts in head and neck squamous cell cancer should logically employ T-cell adjuvants, contrasuppression and immunorestoration. Non-specific stimulation with bacille Calmette-Guerin (BCG), levamisole and other agents has not been successful. Encouraging results have been observed in limited trials with indomethacin and plasmapheresis. Early trials with local administration of low dosages of interferon-alpha, natural interleukin-2 and a natural interleukin mixture have produced partial and complete regressions with no toxicity and with intense leukocyte infiltration indicating cellular immunity. Efforts are needed to define the mechanisms and the antigens involved in these reactions. On the contrary, treatments with high dosages of recombinant interferon-alpha and interleukin-2 have yielded few responses and considerable toxicity. Combination strategies are discussed which may improve upon these initial immunotherapeutic effects of these low dose trials.